Thermodynamic properties study of dissolution of 2-hydroxbenzoic acid in binary solvent (ethanol+ water) at various temperatures11

Abstract

The dissolution of 2-hydroxbenzoic acid in binary solvent (ethanol+water) mixed with various ethanol concentrations was experimentally tested at temperatures from (293 to 313) K under atmospheric pressure by the equilibrium process. As the temperature rose, the degradation of 2-hydroxbenzoic acid in all ethanol concentrations rose. Tower thermodynamic models like the van't Hoff equation, modified Apelblate equation, were correlated with the dissolution results. The measured dissolution with the modified Apelblate equation was found to provide good agreement with experimental values for the behaviors of 2-hydroxbenzoic acid dissolution. On the basis of the van't Hoff study, the thermodynamic properties of the standard dissolution enthalpy ∆H, standard entropy ∆S, and the standard Gibbs free energy ∆G were evaluated. The values of free energy ∆G and enthalpy ∆H were increased as the percentage of ethanol and temperature increased while the values of entropy ∆S were decreased at the same values. The Nonlinear variation of ∆G, ∆H, and ∆S with mole % indicate there is specific solvation occurring in a water-ethanol mixture Discovered iso-kinetic temperature. 268.7 (less than 300) means that there is a weak interaction between solvent and solvent, or there is a slow shift in the solvent or reactant structure, or both.